Marker holder



FIG. 1 is a left side elevational view of a marker holder showing my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom elevational view thereof;

FIG. 5 is a right end view thereof;

FIG. 6 is a left end view thereof; and,

FIG. 7 is a perspective view thereof.

The marker depicted by means of broken lines in FIGS. 1 through 4 and 7 have been shown for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a marker holder, as shown and described. 